This question appears to be off-topic. The users who voted to close gave this specific reason:

"Application/website recommendations are off-topic and out of scope. It is better instead to use a particular web app or website and ask for help in any issues you have with it specifically." – Rubén, Al E., Alex, Sathya

2 Answers
2

In your Google profile, you can use a url to define your profile image.
You can do the same in your gravatar profile. The only place where you can't do that is in facebook.

Your facebook profile picture has a permanent URL, http://graph.facebook.com/username/picture. You can now use that as your profile image in both google and gravatar. That way, the next time you change your picture on facebook, it will be reflected on the other two services.

Edit : just realised you can get a bigger image by using an extra argument in the URL : http://graph.facebook.com/username/picture?type=large

The thing is that many big sites like Google and Facebook don't use Gravatar.
–
cstackJul 2 '10 at 17:12

And I hope they don't. As far as I can tell, Gravatar's business model is as a web usage tracking service. Even if I'm mistaken about that, a single point of aggregation or failure is a Bad Thing.
–
mswJul 4 '10 at 5:57